同步数位阶层 tóngbùshùwèijiēcéng synchronous digital hierarchy Definitions Defs Origin Strokes Stroke Words Sentences Sents 同步数位阶层 同步數位階層 tóngbùshùwèijiēcéng synchronous digital hierarchy synchronous digital hierarchy; SDH
同步数位阶层 同步數位階層 tóngbùshùwèijiēcéng synchronous digital hierarchy synchronous digital hierarchy; SDH
